Research on the Insulating Agent for High-insulation EVA Multi-functional Sheath Film Used in Plastic Additives in China Hu Shouwen Su Jingyu Che Long Wang Huan Gao Jizhi (Shenyang Hualong Agricultural Membrane Manufacturing Co., Ltd., Shenyang 110034) X-ray diffraction, chemical analysis, particle size analysis and application performance It shows that CMS-ultrafine talcum powder is not only a good heat-insulating agent, but also a sustained-release carrier for liquid drops. It can be used in the production of EVA highly translucent, high heat-preserving, flow-proof, drip-reducing and fog-shampening films according to a reasonable formula design.

0 Rumor film research and development has made rapid progress and achieved remarkable results. In recent years, some companies have been striving to develop EVA high-transmittance, high-heat insulation, drip-drop, fog-reducing, and long-lived greenhouse film production, and have been continuously applied in northern energy-saving solar greenhouses. The results show that the transmittance of infrared (7~11Mm) of EVA film decreases with the increase of VA content. EVA film with a thickness of 0.10mm is made of VA 14% EVA resin, the transmittance of infrared (7~11rtn) is about 30%, while the transmittance of infrared film (7~11Mm) of PVC film of the same thickness is about 20%. Compared with the shed film, there is still a certain gap between the insulation of the EVA shed film.

In order to adapt to the requirements of the continuous development of energy-saving over-winter greenhouses and vegetables in the north, it is necessary to increase the insulation of EVA film and develop a highly-insulating EVA multifunctional film.

The addition of a heat-preserving agent (pre-made masterbatch) to EVA is an effective measure to reduce the infrared (7-rate) and heat-insulating properties of EVA film. Since the mid-1980s, various plants have adopted different methods in the production of PE multifunctional film. Insulative agents, the main varieties are kaolin, talc, cinnamon algae, mica-kaolin, calcium carbonate and other inorganic powders.In 1998 China Agricultural Plastics Application Technology Institute of the inorganic insulation agent of the physical and chemical properties, process performance and application performance After the release of the results, after the results were released, they played an important guiding role in the selection of functional PE and EVA insulation films for greenhouse films.We selected ultra-fine inorganic insulation materials according to the needs of EVA high-transmittance and high-heat insulation film production. In addition, the relevant properties of CMS-888 ultra-fine talc powder (the company claims a fineness of 2 500 to 3000 mesh) produced by Heshan Chemical (Haicheng) Co., Ltd. were experimentally studied and applied after EVA film production. Has achieved better results.

Crystal structure and chemical composition of talc powder CMS-888: Kirchhoff's law states: Under the same temperature conditions, for a different object, the ability to absorb a certain wavelength is also better for a certain wavelength of the radiation ability of the object Strong; For the same object, if it emits radiation of a certain wavelength at a temperature T, it can also absorb a certain wavelength of radiation at the same temperature. Talc is a hydrated magnesium silicate mineral. Pure talc is composed of a layer of brucite (MgO°H2O) sandwiched between two basic layers of silica (Si2) and has a flaky (flat) configuration. Most of its products are powdery. The test results show that the talc powder added to the PE, EVA film 1-%Pfc-0i9aladC I can absorb and radiate sVseWm infrared Uw talc after grinding graded, its composition in Table 1. CMS-888 ultra-fine The talc powder X-ray diffraction pattern () is compared with the standard card and confirmed to be a talc crystal structure. The theoretical chemical formula of only a small amount of magnesite (chemical composition is MgC3) talc (hydrated magnesium silicate) is % Haicheng. Talc deposits not only have large reserves, but also have higher grades. It is understood that its main components are stable and its impurity content is low. According to talc theory, the Si2MgO in ultra-fine talc powder is calcu- lated and the loss on ignition is higher than the calculated value of theoretical chemical H2O%. This is related to the presence of a small amount of magnesite (MgC3) but does not affect its use as a heat insulator for EVA film. It is worth noting that the content of Fe23 and Ti2 in CMS-888 ultrafine talcum powder is very low, so it is ideal for use in EVA longevity film.

Table 1 Chemical Analysis Results of Super Fine Talcum Powder of CM888 (Appointed by the Ceramic Quality Inspection Station of Liaoning Province) No. Item and Result 12 MgO/% 32. 2 CMS-888 Particle Size Distribution of Ultra Fine Talcum Powder Heshan Chemical (Haicheng) Co., Ltd. Ultrafine The production process of talcum powder is: The massive talc is crushed into small pieces by a jaw crusher, and the particles that are broken by a ring hammer to 5~8m account for about 25%~30%, and the particles with 10~30Mm account for about 35%, >5~8Mm particles account for about 25%, 10Mm particles, the average particle size and particle size distribution is better.

Table 2 CM888 ultra-fine talc particle size distribution (sedimentation method) test results (entrusted by the inspection of ceramics quality inspection station in Liaoning Province) No. particle size / Mm cumulative percentage /% a few analysis results Description Total need to explain is that Heshan Chemical (Haicheng) Limited The company used laser particle size analyzer (MASTERSIZ-ER) to track and measure the particle size and particle size distribution of CMS-888 ultrafine talc produced in each class. The test results are listed in Table 3. From the comparison between Table 2 and Table 3, CMS-888 ultra-fine talcum powder was detected by a laser particle size analyzer with larger particles (10-23 Mm), higher content of >8 Mm and >5 Mm particles, and application performance of CMS-888 ultra-fine talc powder 3.1 high thermal insulation The mathematical expression of Planck's law in relation to high light transmission shows the variation of the monochromatic radiation power with wavelength for blackbody at different temperatures. Wien's displacement law indicates the wavelength center of the corresponding maximum monochromatic radiation force, which is inversely proportional to the absolute temperature T. (The following C is a constant: 2 The results calculated according to the above formula are shown in Table 4. 10±0.5Mm Infrared transmittance is the main reason for the improvement of subsidence is slow 屈 屈 ― ― 保 保 保 保 保 保 保 保 保 保 保 保 保 保 保 保 保 . . . . . . . . . . . . . . . . . (°C) The relationship between the thickness of the EVA film and the temperature-temperature performance obtained from a certain composite structure (Table 5) is approximately ±1. At 4%, the infrared transmittance of the EVA film was significantly reduced in the range of infrared transmittance and micPublishingHouse.All. After adding appropriate amount of CMS-888 ultrafine talcum powder (1.11.3% in the film) to the EVA film, the infrared transmittance in the wavelength range of 9.5 to 10.5 Mm is more significantly reduced, which can significantly improve the thermal insulation. Sex.

The inorganic insulation agent is added to reduce the transmittance of EVA film (7~11Mm) and improve the insulation. The development of high-heat insulation EVA film must take into account the high transparency of the EVA film and the increase in the room during the daytime. Temperature effect. The results of several tests showed that when the EVA three-layer composite blow molding film for each layer of resin: the outer layer (covered on the shelf frame) and the middle layer of 14/0. 7EVA resin, the inner layer is 5/0. 3EVA and LLDPE mixed resin (mixing ratio is 1:1). When the outer layer, middle layer and inner layer thickness ratio is 3.5:4.0:2.5, the content of CMS-888 ultra-fine talcum powder in each layer is controlled as follows: outer layer 1.12% 1.34% of the middle layer and 0.72% of the inner layer. The EVA three-layer composite film with a thickness of 0.12 mm has a light transmittance of 90.4%, a haze (scattered light transmission ratio) of 27.1%, and infrared rays (7 to 11 Mm). The rate of 20.3% (similar to the infrared transmittance of PVC film), basically meets the requirements of energy-efficient over-winter solar greenhouse EVA film for high transmission and high heat preservation. It is worth noting that the intensity of scattered light is relatively low. If CMS-888 ultrafine talcum powder is added in large amounts, the film haze (scattered light transmission ratio) of the EVA film can be increased, which is not conducive to increasing the temperature in the shed indoors. effect. According to the above formula design, the control thickness is 0.12mm EVA, the film haze is about 25%, can achieve energy-saving winter greenhouse EVA film with a high transmittance, warming and good thermal insulation performance requirements 7. According to Table 5 The composite structure blow-molded thickness 0.12mm EVA multifunctional three-layer composite film, when the film VA content of 11%, CMS-888 ultra-fine talcum powder content of about 20%, the light transmittance can reach 90%. This shows that using EVA resin with high VA content and suitable amount of CMS-888 ultra-fine talc as the heat-insulating agent can produce EVA high-transmittance and high-heat insulation film.

Under a certain composite structure (see Table 5), as the film thickness increases, its light transmittance and infrared transmittance decrease, and the haze increases. As the film thickness decreases, the transmittance and infrared transmittance increase, and the haze decreases (see Table 6 and the approximate conditions). According to the thickness of the shed film required by the user, the composite structure design can be reasonably adjusted so that the three functions of light transmittance, haze, and infrared (7~11Mm) transmittance can meet better requirements.

Table 5 EVA Multi-layer Blown Sheath Film Layers Base Resin and Insulative Additive Levels Outer Middle Layer Inner Layer Thickness Ratio Description (1) 7028 Grade LLDPE is Kuwaiti product, C6 comonomer MFR 1.0g/10min (2) Insulation Agent CMS-888 ultra-fine talcum powder pre-made masterbatch Table 6 according to Table 5 composite structure production of different thickness EVA multi-functional film of the photothermal performance of the approximate (estimated) value film thickness /mm transmittance /% haze /% 3.2 Multifunctional Auxiliaries Slip Resistance and Dispersion of Insulating Agents in Masterbatch Processing Multifunctional Additives (including Drops) In the processing of masterbatches, carrier resins and various types The agent cannot be mixed evenly and the extrusion process does not work properly.

The addition of an appropriate amount of CMS-888 ultra-fine talcum powder can reduce the material slip caused by the dropping agent, so as to achieve the technical requirements for uniform mixing of the carrier resin and various additives and normal extrusion granulation. After the test, according to the formula listed in Table 7, the use of Koya 60 twin-screw extruder, strict control of technical conditions, can normally produce multi-functional additives masterbatch.

Table 7 Multifunctional Auxiliary Auxiliary Auxiliary Auxiliary Formulation for Epoxy Membrane Auxiliaries Name Resin Resin (EVA.PE) Anti-aging Agent Dropping Agent CMS-888 Talcum Powder Mist-reducing Agent Total Number of Parts Membrane Multifunctional Additives Masterbatch Processing micpolishingHouse.Allrights is commonly used in membrane production. People usually use liquid paraffin, stearic acid and stearate, titanate coupling agents or silane coupling agents to activate and disperse inorganic powder additives. In the production of masterbatch for multi-functional additives (including drip agents), the above dispersants or coupling agents should not be used or necessary. Past test results have shown that the use of the dispersant or coupling agent to activate and disperse the inorganic heat-insulating agent powder may obstruct the adsorption and sustained-release of the heat-insulating agent particle on the flowable agent, and therefore the flowability and the flow of the film are dripped. Persistence has an adverse effect; some can reduce the aging resistance of the film and even accelerate the aging of the film. In fact, drip agents (a variety of non-ionic surfactant formulations) are highly effective dispersants for inorganic warmers such as CMS-888 Ultrafine Talcum Powder. According to the designed formula (such as Table 7), the masterbatch is produced, and evenly mixed in EVA resin or EVA and LLDPE, LDPE mixed resin in an appropriate proportion. Under the strict control of extrusion blown film technology The agent (including the insulating agent) can be uniformly dispersed in the resin melt and the film. The appearance of the shed film was examined, no coalesced inorganic matter powder particles were visible, and the light-temperature performance of each part of the shed film was not detected. This is enough to show that the CMS-888 ultra-fine talcum powder has been more uniformly dispersed in the film. In summary, CMS-888 ultra-fine talcum powder is a slip agent for liquid drops, and the liquid drop agent is an efficient dispersant for CMS-888 ultra-fine talcum powder. The interaction between them, in the EVA, PE shed significant practical effect.

3.3 The relationship between the amount of insulating agent and the slow release of the dropping agent. Due to the adsorption effect of the convective drop on the surface of the insulating agent particle, the rate of migration (precipitation) of the flowing agent in the film can be slowed down, thereby improving the drip effect of the film. Sexuality, therefore, some people called insulation agent first-class release sustained release agent. The following tests have been conducted: the outer layer of EVA multifunctional three-layer composite blown film (overlaid on the shed film skeleton) and the middle layer were respectively added with 1.7% and 1.9% of dropping agent, and the ratio of the dropping agent and the heat insulating agent was more than In the process of covering greenhouses overwintering in greenhouses, the shelf life of the films produced according to this formula was 1:0.4. After research, according to Table 8 Table 8 EVA multifunctional three-layer composite film in the amount of additives in the drop and the amount of insulation agent Bubu layer in the inner layer of the inner layer of the film in the flow of drop agent content of insulation agent drops and the amount of insulation agent ratio instructions (1) Various auxiliaries are pre-formed into masterbatch (2) The outer layer is covered on the frame of the shed. Screw diameter 120 L/D*:1 Machine head orifice (1) X-ray diffraction, chemical analysis, particle size analysis With a generous recipe, the ratio of each layer of dripping agent to CMS-888 ultra-fine talcum powder (inhibitor of sustained release carrier for the insulative agent and dripping agent) is controlled to be 1:0.6~0.7, which enables the EVA multifunctional three-layer composite film to have Better drip hold. Under the premise of adopting excellent greenhouse structure and covering film under greenhouse and supporting technology of drip irrigation or underdrain irrigation under the ground film and reasonable control of humidity and temperature in the greenhouse, the drip duration is more than 5 months, which can meet the application requirements of overwintering solar greenhouse. .

Has a flat (flaky) configuration. The use of the adsorbent and sustained-release agent as a dripping agent, whether it can make the shelf film have a better drip holdability remains to be further studied and compared. Some tests have been carried out using a mixture of stronger or finer inorganic powders and CMS-888 ultrafine talc, and the results are elaborated.

3.4 Other properties Discussion The content of transition metal compounds in talc is very low. According to the observations that the use of Haicheng talcum powder (1 250 mesh) for the production of PE and EVA multi-functional greenhouse films, under the premise of reasonable selection of suitable brand resin, strict control of the amount of anti-aging agent added, and the technical conditions of the production technology of the film, the CMS-888 ultrafine talcum powder does not affect the aging resistance of the film.

Among inorganic soaking agents, talcum powder has the lowest hardness. The use of CMS-888 ultra-fine talcum powder as a heat-insulating agent can significantly reduce the wear of the extruder screw and barrel of the extruder and blown film unit for masterbatch production.

Based on the study of the comprehensive performance of 4EVA high-efficiency, high-temperature insulation and long-lasting shed film, the composite structure of each layer of EVA high-transmittance, high-heat insulation and long-lived dripping long-lived shed film was designed and the special masterbatch formula for each layer was designed. The special multi-functional additive masterbatch of each layer was made by using Koya's 60 twin-screw extrusion unit, and a co-extruded three-layer compound wide-width film blowing machine (three extruders with a diameter of 1400 mm and a die gap of 2.2 mm) was adopted. The EVA high-efficiency, high-temperature, long-lasting shed film (see Table 9 and its comprehensive performance) has been produced normally and has been used by many users in the Northeast and North China.

Table 9 Comprehensive Performance of EVA High-Efficiency and High-Density Drop Longevity Films (Shenyang Hualong Agricultural Film Co., Ltd.) Tensile Strength/MPa Elongation at Break/% Right-Angle Tear Strength/km Transmittance/% Aging Resistance ( Service life / month) Longitudinal horizontal Longitudinal horizontal Longitudinal horizontal 5 Conclusion Application performance study results show that, CMS-888 ultra-fine talcum powder can be used as EVA high light efficiency and high temperature drip longevity shed film insulation agent and the slow-release carrier sustained-release carrier. Its production enterprises should strictly control the particle size and particle size distribution and prevent the mixing of impurities.

In the process of manufacturing multi-functional masterbatch by using twin-screw extruder, adding appropriate amount of talc powder CMS-888 can significantly reduce the slippage caused by the dripping agent and make the carrier resin and the multifunctional additive more homogeneously mixed. And the masterbatch production continued to proceed normally.

Effective dispersant, CMS-888 ultrafine talcum powder should not be surface treated with other additives.

Ultrafine talcum powder can make EVA film with high light transmittance and high heat preservation, good temperature increase and drip retention. The EVA multi-functional film with good overall performance is suitable for application in the northern energy-saving overwintering solar greenhouse.

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